Hot tubs or spas are excellent ways for relaxing and rejuvenating, as well as therapeutically soothing sore muscles and body parts. The conventional hot tub is mounted in or above the ground, has rigid sidewalls, typically a molded fiberglass shell for containing water, and a relatively sophisticated and expensive electronically monitored and controlled water heating system relatively permanently connected an existing water supply system. Hot tubs are often combined with standard swimming pools, either close to but spaced from the pool or immediately adjacent thereto separated by a low dividing wall. The ability to switch back and forth from the cold pool water to the hot spa water is extremely exhilarating.
To date, there has not been an economically feasible portable hot tub for use in remote locations away from the backyard. One difficult hurdle in constructing a portable hot tub is the necessity of providing extremely strong sidewalls to contain the large amount of water therein. Of course providing sturdy sidewalls increases the size and weight of the device which hinders portability. One possible answer to this practical problem is to immerse the hot tub in a larger body of water, which equilibrates the hydraulic forces across the spa wall and therefore reduces the structural strength requirements.
Several designs for floating hot tubs, spas and pools are known, including U.S. Pat. Nos. 4,126,905, 4,135,256, 4,754,502, 5,470,480, 6,795,983, and 7,032,258. For a number of reasons, these designs lack one or more of the following: easy portability, easy and rapid setup, stability in turbulent water, or economic practicality. Some relatively recent floating hot tubs, such as in U.S. Pat. No. 6,795,983, commercially available as the HOT POD floating spa, are primarily designed for use in a pool with relatively flexible and lightweight construction, which makes them ill-suited for use in very cold and turbulent water. Indeed, the '983 patent promotes the ability to easily depress the hot tub upper rim to facilitate entry and exit of both people and surrounding ambient water. Hot tubs have been built into larger boats, including crew ships and luxury yachts. Though technically “floating,” these hot tubs are not portable by themselves, and are relatively permanently structurally installed and connected to the electrical and water systems of the boat.
Consequently, there remains a need for a floating hot tub that is portable, easy and quick to set up by one person, stable in rough waters, and within the budget of ordinary consumers.